为什么我的 CPU 核心数是 2，但使用 multiprocessing.cpu_count() 得到 4？

Question

In my Mac: MacBook Pro (Retina, 13-inch, Early 2015)

there is the CPU information:

  Model:                MacBook Pro
  Model description:    MacBookPro12,1
  CPU name:             Dual-Core Intel Core i5
  CPU rate:             2.7 GHz
  CPU number:           1
  Core number:          2

When I use Python execute the code:

from multiprocessing import cpu_count
print(cpu_count())  # 4

there output 4 .

Why not 2?

Answer 1

I think multiprocessing.cpu_count() returns the number of logic cores, not physical ones. For example, I have a surface pro 7, with 4 physical cores and 8 logic ones, and my output is:

>>> print(multiprocessing.cpu_count())
8

Answer 2

Yes multiprocessing.cpu_count() and os.cpu_count() will return logical processors. If you want to check logical and physical processors seperately you can use psutil They can be uses as shown below.

import psutil

print(psutil.cpu_count(logical = False))
print(psutil.cpu_count(logical = True))

output will be

2

4